Light Scattering by Vitreous of Humans With Vision Degrading Myodesopsia From Floaters

Purpose

Vision-degrading myodesopsia (VDM) from vitreous floaters significantly degrades vision and impacts visual quality of life (VQOL), but the relationship to light scattering is poorly understood. This study compared in vitro measures of light scatter and transmission in surgically excised human vitreous to preoperative indexes of vitreous structure, visual function, and VQOL.

Methods

Pure vitreous collected during vitrectomy from 8 patients with VDM had wide-angle straylight measurements and dark-field imaging, performed within 36 hours of vitrectomy. Preoperative VQOL assessment with VFQ-25, contrast sensitivity (CS) measurements with Freiburg acuity contrast testing, and quantitative ultrasonography were compared to light scattering and transmission in vitro.

Results

All indices of vitreous echodensity in vivo correlated positively with straylight at 0.5° (R = 0.708 to 0.775, P = 0.049 and 0.024, respectively). Straylight mean scatter index correlated with echodensity (R = 0.71, P = 0.04) and VQOL (R = -0.82, P = 0.0075). Dark-field measures in vitro correlated with degraded CS in vivo (R = -0.69, P = 0.04). VQOL correlated with straylight mean scatter index (R = -0.823, P = 0.012).

Conclusions

Increased vitreous echodensity in vivo is associated with more straylight scattering in vitro, validating ultrasonography as a clinical surrogate for light scattering. Contrast sensitivity in vivo is more degraded in the presence of dark-field scattering in vitro and VQOL is decreased in patients whose vitreous has increased light scattering. These findings could form the basis for the development of optical corrections for VDM or support new laser treatments, as well as novel pharmacotherapy.

IMAGING RHEGMATOGENOUS RETINAL LESIONS AND PERIPHERAL VITREORETINAL INTERFACE WITH WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

Analyze the peripheral vitreoretinal interface with widefield optical coherence tomography.

METHODS

Retrospective chart analysis and widefield optical coherence tomography in 120 consecutive cases of rhegmatogenous pathology.

RESULTS

There were 166 lesions in 120 eyes, including 106 horseshoe tears, 22 operculated holes, 30 nonoperculated holes, six giant tears, and two peripheral lamellar defects followed for 6.1 ± 1.2 months. Posterior vitreous detachment was present in all eyes (101/101, 100%) with tears and operculated holes, but only in 5/19 eyes (26.3%) with nonoperculated holes ( P < 0.001). Axial vitreous traction was evident at the anterior edge of horseshoe tears (106/106, 100%), but not the posterior border (18/106, 17%, P < 0.001). Operculated holes located posterior to the vitreous base were free from vitreous traction, displaying a morphology similar to the macular hole. Nonoperculated holes were farther anterior with signs of tangential traction in 23/30 (76.7%) cases. Peripheral vitreoschisis was more often associated with nonoperculated holes (25/30, 83.3%), than horseshoe tears (17/106, 16%; P < 0.001). Horseshoe tears and nonoperculated holes were more often associated with retinal detachment (58/106 [54.7%] and 15/30 [50%], respectively) than operculated holes (5/22, 22.7%), P = 0.023.

CONCLUSION

Peripheral vitreoretinal interactions are similar to vitreomaculopathies, with axial and vitreoschisis-related tangential traction playing different roles in different rhegmatogenous pathologies. Peripheral optical coherence tomography improves understanding of pathophysiology and risks of retinal detachment.

[Vitreoretinal surgery in age-related macular degeneration]

The structure of the vitreous body, its interaction with the retinal surface and tractive alterations of the vitreoretinal interface may play a role in the pathogenesis and the development of age-related macular degeneration (AMD). From clinical trials it can be concluded that posterior vitreous detachment (PVD) or vitreous removal may protect against the development of neovascular AMD. Vitreomacular adhesions may promote neovascular AMD and may have an impact on the efficacy and frequency of intravitreal vascular endothelial growth factor (VEGF) inhibition. Therefore, vitreomacular surgery may be considered as a treatment option in selected cases. Peeling of epimacular membranes and the internal limiting membrane (ILM) may contribute to stabilizing visual acuity and reducing the treatment burden of current intravitreal pharmacotherapy. At present, surgical interventions in AMD are mainly performed in cases of submacular hemorrhage involving the fovea. The treatment is not standardized and consists of liquefaction of the blood using recombinant tissue plasminogen activator (rTPA) and its pneumatic displacement, potentially combined with VEGF inhibition. Other submacular surgical strategies, such as choroidal neovascularization (CNV) extraction, macular translocation or transplantation of retinal pigment epithelium (RPE) are currently limited to selected cases as a salvage treatment; however, the development of these submacular surgical interventions has formed the basis for new approaches in the treatment of dry and neovascular AMD including submacular or intravitreal gene and stem cell therapy.

[Role of vitreous in the pathogenesis of neovascular age-related macular degeneration]

Age-related changes in vitreous molecular and anatomic morphology begin early in life and involve two major processes: vitreous liquefaction and weakening of vitreo-retinal adhesion. An imbalance in these two processes results in anomalous posterior vitreous detachment (PVD), which comprises, among other conditions, vitreo-macular adhesion (VMA) and traction (VMT). VMA is more common in patients with neovascular age-related macular degeneration (nAMD) than age-matched control patients, with the site of posterior vitreous adherence to the inner retina correlating with location of neovascular complexes. The pernicious effects of an attached posterior vitreous on age-related macular degeneration (AMD) progression involve mechanical forces, enhanced fluid influx and inflammation in and between the retinal layers, hypoxia leading to an accumulation of vascular endothelial growth factor (VEGF) and other stimulatory cytokines, and probably an infiltration of hyalocytes. It has been shown that vitrectomy not only mitigates progression to end-stage AMD, but existing choroidal neovascularization regresses after surgery. Thus, surgical PVD induction during vitrectomy or by pharmacologic vitreolysis may be considered in non-responders to anti-VEGF treatment with concomitant VMA.

Machine Independence of Ultrasound-Based Quantification of Vitreous Echodensities

Purpose

Quantitative ultrasound (QUS) provides objective indices of Vision Degrading Myodesopsia (VDM) that correlate with contrast sensitivity (CS). To date, QUS methods were only tested on a single ultrasound machine. Here, we evaluate whether QUS measurements are machine independent.

Methods

In this cross-sectional study, 47 eyes (24 subjects; age = 53.2 ± 14.4 years) were evaluated with Freiburg acuity contrast testing (%Weber), and ultrasonography using 2 machines: one with a 15-MHz single-element transducer and one with a 5-ring, 20-MHz annular-array. Images were acquired from each system in sequential scans. Artifact-free, log-compressed envelope data were processed to yield three parameters (mean amplitude, M; energy, E; and percentage filled by echodensities, P50) and a composite score (C). A B-mode normalization method was applied to the 20-MHz datasets to match QUS parameters at both frequencies. Statistical analyses were performed to evaluate correlations among CS, E, M, P50, and C for both machines.

Results

QUS parameters from each machine correlated with CS (R ≥ 0.57, P < 0.001) and there was correlation between machines (R ≥ 0.84, P < 0.001). Correlations between CS and QUS parameters were statistically similar for both machines (P ≥ 0.14) except when the 20-MHz data were normalized (P = 0.04). Reproducibility of QUS parameters computed from 20-MHz data were satisfactory (52.3%-96.3%) with intraclass correlation values exceeding 0.80 (P < 0.001).

Conclusions

The high correlation between QUS parameters from both machines combined with a statistically similar correlation to CS suggests QUS is an effective, machine-independent, quantitative measure of vitreous echodensities.

Translational Relevance

QUS may be applied across clinical ophthalmic ultrasound scanners and imaging frequencies to effectively evaluate VDM.

RECURRENT FLOATERS AFTER LIMITED VITRECTOMY FOR VISION DEGRADING MYODESOPSIA

PURPOSE

Limited vitrectomy improves vision degrading myodesopsia, but the incidence of recurrent floaters postoperatively is not known. We studied patients with recurrent central floaters using ultrasonography and contrast sensitivity (CS) testing to characterize this subgroup and identify the clinical profile of patients at risk of recurrent floaters.

METHODS

A total of 286 eyes (203 patients, 60.6 ± 12.9 years) undergoing limited vitrectomy for vision degrading myodesopsia were studied retrospectively. Sutureless 25G vitrectomy was performed without intentional surgical posterior vitreous detachment (PVD) induction. CS (Freiburg Acuity Contrast test: Weber index, %W) and vitreous echodensity (quantitative ultrasonography) were assessed prospectively.

RESULTS

No eyes (0/179) with preoperative PVD experienced new floaters. Recurrent central floaters occurred in 14/99 eyes (14.1%) without complete preoperative PVD (mean follow-up = 39 months vs. 31 months in 85 eyes without recurrent floaters). Ultrasonography identified new-onset PVD in all 14 (100%) recurrent cases. Young (younger than 52 years; 71.4%), myopic (≥-3D; 85.7%), phakic (100%) men (92.9%) predominated. Reoperation was elected by 11 patients, who had partial PVD preoperatively in 5/11 (45.5%). At study entry, CS was degraded (3.55 ± 1.79 %W) but improved postoperatively by 45.6% (1.93 ± 0.86 %W, P = 0.033), while vitreous echodensity reduced by 86.6% ( P = 0.016). New-onset PVD postoperatively degraded CS anew, by 49.4% (3.28 ± 0.96 %W; P = 0.009) in patients electing reoperation. Repeat vitrectomy normalized CS to 2.00 ± 0.74%W ( P = 0.018).

CONCLUSION

Recurrent floaters after limited vitrectomy for vision degrading myodesopsia are caused by new-onset PVD, with younger age, male sex, myopia, and phakic status as risk factors. Inducing surgical PVD at the primary operation should be considered in these select patients to mitigate recurrent floaters.

3-D OCT imaging of hyalocytes in partial posterior vitreous detachment and vaso-occlusive retinal disease

Purpose

To describe the spatial distribution and morphologic characteristics of macrophage-like cells called hyalocytes in the posterior vitreous cortex of a patient with unilateral partial posterior vitreous detachment (PVD) using coronal plane en face optical coherence tomography (OCT).

Observations

A 54-year-old male with sickle cell disease (HbSC genotype) presented with a partial PVD in one eye. Rendered volumes of a slab extending from 600 μm to 3 μm anterior to the inner limiting membrane (ILM) revealed hyperreflective foci in the detached posterior vitreous cortex suspended anterior to the macula, likely representing hyalocytes. In the fellow eye without PVD, hyperreflective foci were located 3 μm anterior to the ILM. The morphology of the cells in the eye with PVD varied between a ramified state with multiple elongated processes and a more activated state characterized by a plump cell body with fewer retracted processes. In the same anatomical location, the hyperreflective foci were 10-fold more numerous in the patient with vaso-occlusive disease than in an unaffected, age-matched control.

Conclusions and Importance

Direct, non-invasive, and label-free techniques of imaging cells at the vitreoretinal interface and within the vitreous body is an emerging field. The findings from this case report suggest that coronal plane en face OCT can be used to provide a detailed and quantitative characterization of cells at the human vitreo-retinal interface in vivo. Importantly, this case report demonstrates that 3D-OCT renderings can enhance visualization of these cells in relation to the ILM, which may provide clues concerning the identity and contribution of these cells to the pathogenesis of vitreo-retinal diseases.

Vitrectomy Improves Contrast Sensitivity in Multifocal Pseudophakia With Vision Degrading Myodesopsia

PURPOSE

Multifocal intraocular lenses (MFIOL) are associated with degradation in contrast sensitivity function (CSF); yet the contribution of vitreous is not known, nor is the benefit of vitrectomy.

DESIGN

Prospective, nonrandomized clinical study.

METHODS

A total of 180 eyes of 180 patients (55 MFIOL, 60 monofocal intraocular lenses [MIOL], 65 phakic) with symptomatic vitreous opacities were enrolled. Vitreous structure was assessed with quantitative ultrasonography (QUS). Vision was evaluated with visual acuity and CSF measurements.

RESULTS

Vitreous echodensity was the same in all lens cohorts, yet CSF was worse in MFIOL eyes (P < .001). In 86 patients who elected vitrectomy, there was 68% greater vitreous echodensity and 31% worse CSF than in observation controls (P < .0001 for each). Preoperatively, CSF was 25% worse in MFIOL than in MIOL (P = .014). Postoperatively, vitreous echodensity decreased by 55%, 51%, and 52%, whereas CSF improved by 37% 48% in and 43% in MFIOL, MIOL, and phakic eyes, respectively (P < .0001 for each). NEI Visual Function Questionnaire analyses showed improved visual well-being.

CONCLUSIONS

Patients with vision degrading myodesopsia who elected vitrectomy had greater vitreous echodensity and worse CSF than controls, but no other differences in age, sex, or myopia. MFIOL eyes had worse CSF than MIOL and phakic eyes, very possibly due to combined effects of the MFIOL and vitreous opacification. Limited vitrectomy reduced vitreous echodensity and improved CSF in all eyes. All patients with CSF-degrading vitreous opacities benefited from limited vitrectomy, including those with MFIOL. As MFIOL eyes had 37% improvement in CSF, patients with MFIOL and vision degrading myodesopsia merit consideration of vitrectomy.

Laser-induced nanobubbles safely ablate vitreous opacities in vivo

In myopia, diabetes and ageing, fibrous vitreous liquefaction and degeneration is associated with the formation of opacities inside the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause notable impairment in vision-related quality of life. Here we introduce 'nanobubble ablation' for safe destruction of vitreous opacities. Following intravitreal injection, hyaluronic acid-coated gold nanoparticles and indocyanine green, which is widely used as a dye in vitreoretinal surgery, spontaneously accumulate on collagenous vitreous opacities in the eyes of rabbits. Applying nanosecond laser pulses generates vapour nanobubbles that mechanically destroy the opacities in rabbit eyes and in patient specimens. Nanobubble ablation might offer a safe and efficient treatment to millions of patients suffering from debilitating vitreous opacities and paves the way for a highly safe use of pulsed lasers in the posterior segment of the eye.

Hyalocyte origin, structure, and imaging

Introduction

Hyalocytes have been recognized as resident tissue macrophages of the vitreous body since the mid-19^th century. Despite this, knowledge about their origin, turnover, and dynamics is limited.

Areas covered

Historically, initial studies on the origin of hyalocytes used light and electron microscopy. Modern investigations across species including rodents and humans will be described. Novel imaging is now available to study human hyalocytes in vivo. The shared ontogeny with retinal microglia and their eventual interdependence as well as differences will be discussed.

Expert opinion

Owing to a common origin as myeloid cells, hyalocytes and retinal microglia have similarities, but hyalocytes appear to be distinct as resident macrophages of the vitreous body.

Carbon quantum dots as a dual platform for the inhibition and light-based destruction of collagen fibers: implications for the treatment of eye floaters

Common in myopia and aging, vitreous opacities arise from clumped collagen fibers within the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause significant impairment in vision-related quality-of-life, representing an unmet and underestimated medical need. One therapeutic approach could be the use of versatile light-responsive nanostructures which (i) interfere with the formation of collagen fibers and/or (ii) destroy aggregates of vitreous collagen upon pulsed-laser irradiation at low fluences. In this work, the potential of positively and negatively charged carbon quantum dots (CQDs) to interfere with the aggregation of type I collagen is investigated. We demonstrate that fibrillation of collagen I is prevented most strongly by positively charged CQDs (CQDs-2) and that pulsed-laser illumination allowed to destroy type I collagen aggregates and vitreous opacities (as obtained from patients after vitrectomy) treated with CQDs-2.

Volumetric Optical Imaging and Quantitative Analysis of Age-Related Changes in Anterior Human Vitreous

Purpose

The purpose of this study was to characterize age-related changes in anterior human vitreous with 3-D swept source optical coherence tomography (SS-OCT) and evaluate associations with axial length (AL) and contrast sensitivity function (CSF).

Methods

There were 49 phakic eyes in 49 patients (40.0 ± 19.3 years) had 3-D volumetric scanning of the lens and retrolental vitreous with SS-OCT at 1050 nm. OCT-derived indices of vitreous optical density (VOD), vitreous opacification ratio (VOR), and lens optical density (LOD) were correlated with AL and double-pass assessment of retinal point spread function (Objective Scatter Index [OSI]). CSF was measured using an adaptive-optics visual simulator (area under log-log contrast sensitivity function [AULCSF]).

Results

Vitreous SS-OCT detected gel vitreous, liquefied lacunae, Berger's space, retrolental laminae, and fibrous opacifications. VOD, VOR, and LOD showed high reproducibility (intraclass correlation coefficients 0.968, 0.975, and 0.998, respectively). VOD was highly correlated with VOR (Pearson's R = 0.96, P < 0.000001). VOD, VOR, and LOD correlated with age (R = 0.48, 0.58, and 0.85, P < 0.001 for each). VOR and LOD correlated with OSI (R = 0.36, P = 0.0094, and R = 0.36, P = 0.0096, respectively). VOR correlated negatively with AULCSF (R = −0.53, P < 0.00009), which was related to OSI. Myopic eyes had higher OSI than nonmyopic eyes (P = 0.0121), consistent with correlation between OSI and AL (R = 0.37, P = 0.0091). Multivariable regression confirmed these findings.

Conclusions

SS-OCT visualized microstructural features of anterior human vitreous, where opacification is associated with increased light scattering and CSF degradation. SS-OCT enables high-resolution optical evaluation of vitreous opacities.

Vitreous and Vision Degrading Myodesopsia

Macromolecules comprise only 2% of vitreous, yet are responsible for its gel state, transparency, and physiologic function(s) within the eye. Myopia and aging alter collagen and hyaluronan association causing concurrent gel liquefaction and fibrous degeneration. The resulting vitreous opacities and collapse of the vitreous body during posterior vitreous detachment are the most common causes for the visual phenomenon of vitreous floaters. Previously considered innocuous, the vitreous opacities that cause floaters sometimes impact vision by profoundly degrading contrast sensitivity function and impairing quality-of-life. While many people adapt to vitreous floaters, clinically significant cases can be diagnosed with Vision Degrading Myodesopsia based upon echographic assessment of vitreous structure and by measuring contrast sensitivity function. Perhaps due to the ubiquity of floaters, the medical profession has to date largely ignored the plight of those with Vision Degrading Myodesopsia. Improved diagnostics will enable better disease staging and more accurate identification of severe cases that merit therapy. YAG laser treatments may occasionally be slightly effective, but vitrectomy is currently the definitive cure. Future developments will usher in more informative diagnostic approaches as well as safer and more effective therapeutic strategies. Improved laser treatments, new pharmacotherapies, and possibly non-invasive optical corrections are exciting new approaches to pursue. Ultimately, enhanced understanding of the underlying pathogenesis of Vision Degrading Myodesopsia should result in prevention, the ultimate goal of modern Medicine.

Vitreous Antioxidants, Degeneration, and Vitreo-Retinopathy: Exploring the Links

The transparent vitreous body, which occupies about 80% of the eye’s volume, is laden with numerous enzymatic and non-enzymatic antioxidants that could protect the eye from oxidative stress and disease. Aging is associated with degeneration of vitreous structure as well as a reduction in its antioxidant capacity. A growing body of evidence suggests these age-related changes may be the precursor of numerous oxidative stress-induced vitreo-retinopathies, including vision degrading myodesopsia, the clinically significant entoptic phenomena that can result from advanced vitreous degeneration. Adequate intravitreal antioxidant levels may be protective against vitreous degeneration, possibly preventing and even improving vision degrading myodesopsia as well as mitigating various other vitreo-retinopathies. The present article is, therefore, a review of the different antioxidant molecules within vitreous and the inter-relationships between vitreous antioxidant capacity and degeneration.

Cost-Effectiveness of Limited Vitrectomy for Vision-Degrading Myodesopsia

PURPOSE

Patients afflicted with clinically significant vitreous floaters suffer from vision-degrading myodesopsia, characterized by impairment in contrast sensitivity function (CSF) and decreased quality of life. This study determined the cost-effectiveness of limited vitrectomy for this condition.

DESIGN

Retrospective, interventional case series and third-party insurer cost-utility analysis.

METHODS

Sixty-seven patients suffering from unilateral vitreous floaters (20 non-myopic patients with posterior vitreous detachment [PVD]; 17 myopic patients [>-2 diopters] without PVD; 30 myopic patients with PVD) completed the National Eye Institute Visual Function Questionnaire (VFQ-39) and were tested with best-corrected visual acuity (BCVA) and CSF measurements before and after limited vitrectomy. A reference case cost-utility analysis was performed.

RESULTS

The mean VFQ-39 increased 19% (P < 0.00001) after surgery, with general vision improving 27% for the entire group and 37% for non-myopic PVD (P < 0.00001 for each). VFQ-39 correlations with time tradeoff utilities indicated a 14.4% improvement in quality of life. Mean BCVA improved 13.5% postoperatively (P < 0.00001) and CSF improved 53% (P < 0.00001). The incremental patient value gain conferred by limited vitrectomy was 2.38 quality-adjusted life-years (QALYs), and the average cost-utility ratio in 2018 U.S. real dollars was $1,574/QALY.

CONCLUSIONS

Limited vitrectomy for vision-degrading myodesopsia is clinically effective, in that it improves BCVA, CSF, and patient well-being. It is also highly cost-effective ($1,574/QALY), with an average cost-utility ratio vs. no therapy that is superior to cataract surgery ($2,262/QALY), amblyopia therapy ($2,710/QALY), and retinal detachment repair ($45,304/QALY). Myopic patients without PVD had the lowest cost-utility ratio of all ($1,338/QALY).

Photoablation of Human Vitreous Opacities by Light-Induced Vapor Nanobubbles

Myopia, diabetes, and aging are the main causes of progressive vitreous collagen aggregation, resulting in vitreous opacities, which can significantly disturb vision. As vitreous opacities, which induce the visual phenomenon of "floaters", are accessible with nanomaterials and light, we propose a nanotechnology-based approach to locally ablate them with highly reduced light energy compared to the more traditional YAG laser therapy. Our strategy relies on the plasmon properties of gold nanoparticles that generate vapor nanobubbles upon pulsed-laser illumination whose mechanical force can ablate vitreous opacities. We designed gold nanoparticles coated with hyaluronic acid (HA), which have excellent diffusional mobility in human vitreous, an essential requirement to reach the vitreous opacities. In addition, we found that HA-coated gold nanoparticles can accumulate extensively on human vitreous opacities that were obtained by vitrectomy from patients with vision-degrading myodesopsia. When subsequently applying nanosecond laser pulses, the collagen aggregates were efficiently destroyed with ∼1000 times less light energy than typically used in YAG laser therapy. This low-energy "floater-specific destruction", which is due to the accumulation of the small gold nanoparticles on the opacities, is attractive, as it may be safer to the surrounding ocular tissues while at the same time being easier and faster to apply compared to YAG laser therapy, where the opacities need to be ablated piece by piece by a tightly focused laser beam. Gold nanoparticle-assisted photoablation may therefore provide a safer, faster, and more reliable destruction of vitreous opacities in the treatment of ophthalmologic diseases.

Assessment of Vitreous Structure and Visual Function after Neodymium:Yttrium-Aluminum-Garnet Laser Vitreolysis

PURPOSE

Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treatment is performed on vitreous floaters, but studies of structural and functional effects with objective outcome measures are lacking. This study evaluated Nd:YAG laser effects by comparing participants with vitreous floaters who previously underwent laser treatment with untreated control participants and healthy persons without vitreous floaters using quantitative ultrasonography to evaluate vitreous structure and by measuring visual acuity and contrast sensitivity function to assess vision.

DESIGN

Retrospective, comparative study.

PARTICIPANTS

One eye was enrolled for each of 132 participants: 35 control participants without vitreous floaters, 59 participants with untreated vitreous floaters, and 38 participants with vitreous floaters previously Nd:YAG-treated. Of these, 25 were dissatisfied and sought vitrectomy; 13 were satisfied with observation.

METHODS

The 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) to assess participant visual well-being, quantitative ultrasonography (QUS) to measure vitreous echodensity, and best-corrected visual acuity (BCVA) and contrast sensitivity function (CSF) to evaluate vision.

MAIN OUTCOME MEASURES

Results of NEI-VFQ-39, QUS, BCVA, and CSF.

RESULTS

Compared with control participants without vitreous floaters, participants with untreated vitreous floaters showed worse NEI-VFQ-39 results, 57% greater vitreous echodensity, and significant (130%) CSF degradation (P < 0.001 for each). Compared with untreated eyes with vitreous floaters, Nd:YAG-treated eyes had 23% less vitreous echodensity (P < 0.001), but no differences in NEI-VFQ-39 (P = 0.51), BCVA (P = 0.42), and CSF (P = 0.17) results. Of 38 participants with vitreous floaters who previously were treated with Nd:YAG, 25 were dissatisfied and seeking vitrectomy, whereas 13 were satisfied with observation. Participants seeking vitrectomy showed 24% greater vitreous echodensity (P = 0.018) and 52% worse CSF (P = 0.006). Multivariate linear regression models confirmed these findings.

CONCLUSIONS

As a group, participants previously treated with Nd:YAG laser for bothersome vitreous floaters showed less dense vitreous, but similar visual function as untreated control participants with vitreous floaters. Because some treated eyes showed less dense vitreous and better visual function than those of untreated control participants, a prospective randomized study of Nd:YAG laser treatment of vitreous is warranted, using uniform laser treatment parameters and objective quantitative outcome measures.

Asteroid hyalosis-a comprehensive review

Asteroid hyalosis is a relatively common cause of vitreous opacities, which is possibly associated with diabetes mellitus and hereditary pigmentary retinopathies. We review the history, epidemiology, and biochemistry of asteroid hyalosis, as well as its relationship with ocular and systemic conditions. We describe imaging modalities used for diagnostic evaluations in cases of severe asteroid hyalosis and propose hypotheses regarding its lack of significant effects on vision. We discuss cataract surgery in patients with asteroid hyalosis and the selection of intraocular lenses for implantation.

Long-Term Safety and Efficacy of Limited Vitrectomy for Vision Degrading Vitreopathy Resulting from Vitreous Floaters

PURPOSE

Vitreous floaters can lower visual acuity (VA) and degrade contrast sensitivity function (CSF). Limited vitrectomy improves VA and normalizes CSF, but long-term results in a large series with objective quantitative outcome measures are lacking.

DESIGN

Case series.

PARTICIPANTS

One hundred ninety-five eyes of 145 patients (87 men, age = 57.6 ± 4.3 years; 58 women, age = 61.5 ± 12.0 years) reporting bothersome vitreous floaters were compared to 70 age-matched controls. Posterior vitreous detachment (PVD) alone was the cause in 96/195 (49.2%), myopic vitreopathy alone was the cause in 30/195 (15.4%), PVD with myopic vitreopathy was the cause in 56/195 (28.7%), and asteroid hyalosis was the cause in 13/195 eyes (6.7%).

METHODS

Limited vitrectomy with 25-gauge instruments was performed without surgical PVD induction, preserving 3 to 4 mm of retrolental vitreous in phakic eyes. Follow-up averaged 32.6 ± 23.5 months (range, 3-115 months), with 2 years or more in 144 eyes, 3 years or more in 69 eyes, 4 years or more in 51 eyes, and 5 years or more in 24 eyes.

MAIN OUTCOME MEASURES

Visual acuity, 39-item National Eye Institute Visual Function Questionnaire (VFQ) results, CSF (Weber index), and quantitative ultrasonography results.

RESULTS

After surgery, vitreous echodensity decreased by 94.1% (P < 0.0001) and VFQ results improved by 19.3% (P < 0.0001). Preoperative VA was 0.68 ± 0.21, improving to 0.77 ± 0.19 after surgery (P < 0.0001). Preoperative CSF was degraded by 91.3% compared with controls (P < 0.0001), normalizing at 1, 3, 6, 12, 24, 36, and 48 months after surgery (P < 0.00005 for each). There were no cases of endophthalmitis. There were 3 retinal tears and 3 retinal detachments that underwent successful repair. Clinically significant vitreous hemorrhage developed in 2 patients, clearing spontaneously. Two macular puckers and 4 recurrent floaters from new PVD were cured by re-operation. Cataract surgery occurred in 21 of 124 patients (16.9%; mean age, 64 ± 7 years; none younger than 53 years), an average of 13.1 ± 6.8 months after vitrectomy.

CONCLUSIONS

Limited vitrectomy for Vision Degrading Vitreopathy decreases vitreous echodensity, improves patient well-being, improves VA, and normalizes CSF. The long-term efficacy and safety profiles suggest this may be a safe and effective treatment for clinically significant vitreous floaters, warranting a prospective randomized trial.

Decision-Making in Medical Research and Clinical Practice: Theory and Methodology of Laboratory Data Evaluation by Predictors, Indicators and Indices

A method designed to aid clinical decision-making is described. Predictors and Indicators are criteria that reflect the likelihood of disease and health, based on a retrospective analysis of the frequencies of diseases or diagnoses associated with symptoms, signs, and tests (SST’s). The approach is primarily based upon the SST’s of an individual and how these vary over time. This differs from traditional approaches which operate primarily from a disease-or diagnostic-oriented perspective. Such approaches are, therefore, useful in areas of medical research, education, and paraclinical service units, but have a limited value for patient-care. Static and dynamic health indices aid clinical decision-making by summarizing the SST-oriented Predictor and Indicator evaluations into individualized indices that can be monitored over time.

The methodology of employing this approach for the evaluation of laboratory data is presented. The application of these techniques to a battery of laboratory tests will be presented in the near future.

Degradation of Contrast Sensitivity Function Following Posterior Vitreous Detachment

PURPOSE

To evaluate the effect of posterior vitreous detachment (PVD) on contrast sensitivity function (CSF) in previously normal eyes, with the hypothesis that PVD reduces CSF.

DESIGN

Prospective observational case series.

METHODS

At a single clinical practice 28 eyes were evaluated: 8 eyes of 8 adults (mean age 54.4 ± 10.1 years; range 39-68 years) with normal CSF documented by Freiburg Acuity Contrast Testing (Weber index: %W) who subsequently experienced PVD, as confirmed by ultrasonography and optical coherence tomography; 8 fellow eyes without PVD; and 12 control eyes: 9 eyes with PVD in patients who chose observation and 3 fellow eyes without PVD.

RESULTS

At study entry there was no significant difference in CSF of fellow eye controls (mean 1.44 ± 0.27 %W; range 1.06-2.00 %W) and eyes that subsequently developed PVD (1.81 ± 0.61 %W; P = .146; range 1.01-2.69 %W). Following PVD there was a 52.5% reduction in CSF (2.76 ± 0.30 %W; P = .001; range 2.25-3.14 %W). CSF in the patients who chose limited vitrectomy (2.51 ± 0.46 %W; range 2.03-3.06 %W) was 41.8% worse than in the eyes with PVD of patients who chose observation (1.46 ± 0.21 %W; P = .001; range 1.08-1.87 %W). After vitrectomy, CSF improved by an average of 43.2%, normalizing in each case at 1 month (CSF 1.51 ± 0.28 %W; P = .001; range 1.14-2.00 %W), 3 months (1.38 ± 0.10 %W; P = .0002; range 1.28-1.51 %W), and 12 months (1.34 ± 0.34 %W; P = .0001; range 1.01-1.89 %W, n = 5) postoperatively, attaining the same CSF as the control fellow eyes (1.34 ± 0.20 %W; range 1.06-1.56 %W).

CONCLUSION

PVD is associated with significant reduction in CSF of previously normal eyes. This quantifiable negative impact on visual function can distinguish patients who are not significantly bothered by vitreous floaters from those with clinically significant symptoms.

Floaters and reduced contrast sensitivity after successful pharmacologic vitreolysis with ocriplasmin

Purpose

To describe the onset of floaters and reduction in contrast sensitivity (CS) following successful pharmacologic vitreolysis with ocriplasmin for the treatment of vitreo-macular traction (VMT) in a patient with previously normal CS.

Observations

A 65-year-old woman with a past ocular history of normal visual acuity (VA = 20/26) and contrast sensitivity (1.81% Weber) presents with a 4-month history of distortions. VA decreased to 20/40 and Optical Coherence Tomography (OCT) demonstrated VMT. Pharmacologic vitreolysis was performed with intravitreal ocriplasmin. Ten weeks later the patient complained of floaters and was found to have a PVD and complete resolution of VMT. VA was still 20/40, but contrast sensitivity decreased by more than 100% to 3.77%Weber. After 6 months of attempted coping, this did not improve, so limited vitrectomy was performed. Post-operative VA = 20/26 and CS improved by 46% from 3.77%W to 2.03%W (normal).

Conclusion

and importance: This case highlights a little discussed consequence of PVD induction by successful pharmacologic vitreolysis - the development of clinically significant floaters. The resulting reduction of contrast sensitivity was normalized by limited vitrectomy, strongly suggesting that the detached vitreous was the cause.

Paradigm Shifts in Ophthalmic Diagnostics

PURPOSE

Future advances in ophthalmology will see a paradigm shift in diagnostics from a focus on dysfunction and disease to better measures of psychophysical function and health. Practical methods to define genotypes will be increasingly important and non-invasive nanotechnologies are needed to detect molecular changes that predate histopathology.

METHODS

This is not a review nor meant to be comprehensive. Specific topics have been selected to illustrate the principles of important paradigm shifts that will influence the future of ophthalmic diagnostics. It is our impression that future evaluation of vision will go beyond visual acuity to assess ocular health in terms of psychophysical function. The definition of disease will incorporate genotype into what has historically been a phenotype-centric discipline. Non-invasive nanotechnologies will enable a paradigm shift from disease detection on a cellular level to a sub-cellular molecular level.

RESULTS

Vision can be evaluated beyond visual acuity by measuring contrast sensitivity, color vision, and macular function, as these provide better insights into the impact of aging and disease. Distortions can be quantified and the psychophysical basis of vision can be better evaluated than in the past by designing tests that assess particular macular cell function(s). Advances in our understanding of the genetic basis of eye diseases will enable better characterization of ocular health and disease. Non-invasive nanotechnologies can assess molecular changes in the lens, vitreous, and macula that predate visible pathology. Oxygen metabolism and circulatory physiology are measurable indices of ocular health that can detect variations of physiology and early disease.

CONCLUSIONS

This overview of paradigm shifts in ophthalmology suggests that the future will see significant improvements in ophthalmic diagnostics. The selected topics illustrate the principles of these paradigm shifts and should serve as a guide to further research and development. Indeed, successful implementation of these paradigm shifts in ophthalmology may provide useful guidance for similar developments in all of healthcare.

Quantifying Visual Dysfunction and the Response to Surgery in Macular Pucker

PURPOSE

To measure the effects of macular pucker (MP) on macular structure and quantify function by measuring visual acuity (VA), contrast sensitivity (CS), and distortions. The effects of surgery were quantitatively evaluated using these measures.

DESIGN

Prospective, comparative case series.

PARTICIPANTS

Fifty-three patients with unilateral MP and normal fellow eyes: 24 operated MP subjects, 17 unoperated controls, and 12 reproducibility subjects.

METHODS

Posterior vitreous detachment was diagnosed by ultrasound and ellipsoid zone disruption (EZD) was determined by OCT, which also measured macular thickness and volume. Vision was assessed, by measuring VA (logMAR) and CS (Freiburg acuity contrast testing: Weber index, %W). A visual distortions index (%DI) was calculated using 3-dimensional threshold Amsler grid testing. Comparisons to controls were performed before surgery and at 1, 3, 6, and 12 months after vitrectomy/membrane peel without chromodissection.

MAIN OUTCOME MEASURES

Posterior vitreous detachment (ultrasound), EZD (OCT), macular thickness and volume (OCT), VA (logMAR), CS (%W), distortions (%DI).

RESULTS

Posterior vitreous detachment was present in 90% of MP eyes, but only 50% of fellow eyes (P < 0.001). All structural and functional indices were worse (28% to 5-fold) in the 24 operated MP eyes than the 17 unoperated MP eyes (P < 0.001). Before surgery, EZD was present in 33% of operated MP eyes but none of the unoperated MP eyes (P < 0.02). The macula was thicker (514±85 μm vs. 257±59 μm; P < 0.001) with greater volume (3.22±0.56 μl vs. 2.14±0.22 μl; P < 0.001) in operated MP eyes than normal fellow eyes. Before surgery, MP eyes had VA = 0.53 logMAR (Snellen equivalent, 20/67) vs. controls = 0.21 (20/32); P < 0.001; CS was 8.61±5.36 %W vs. controls = 3.71±1.47 %W (P < 0.001); and distortions were 7.61±12.6 %DI vs. controls = 0.13±0.61 %DI (P < 0.001). EZD was associated with worse VA (P < 0.01) and CS (P < 0.03) before and after surgery. Each outcome measure improved progressively at 1, 3, 6, and 12 months after surgery, but only %DI and macular volume normalized.

CONCLUSIONS

These quantitative measures characterize the impact of MP on macular structure and function. All indices improved after surgery, but only distortions and macular volume normalized. Contrast sensitivity measurements and quantification of distortions can objectively assess visual dysfunction in MP and may be useful outcome measures of therapy.

Proteomic Analysis of Embryonic and Young Human Vitreous

PURPOSE

The proteomic profile of vitreous from second-trimester human embryos and young adults was characterized using mass spectrometry and analyzed for changes in protein levels that may relate to structural changes occurring during this time. This vitreous proteome was compared to previous reports to confirm proteins already identified and reveal novel ones.

METHODS

Vitreous from 17 human embryos aged 14 to 20 weeks gestation (WG) and from a 12-, a 14-, a 15-, and a 28-year-old was individually analyzed using tandem mass spectrometry-based proteomics. Peptide spectral count associations with embryonic age were assessed using a general linear model of fold changes and Spearman's rank correlation. Differences between embryonic and young adult vitreous proteomes were also compared. Immunohistochemistry was used to evaluate three proteins in five additional fetal (10-18 WG) human eyes.

RESULTS

There were 1217 proteins identified in fetal and young adult human vitreous, 206 after quantile normalization and variance filtering. In embryos, the peptide counts of 37 proteins changed significantly from 14 to 20 WG: 75.7% increased, 24.3% decreased. Immunohistochemistry confirmed the absence of clusterin and cadherin in 10 and 14 WG eyes and their presence at 18 WG. Comparing embryonic to young adult vitreous, 47 proteins were significantly higher or lower. A total of 768 proteins not previously identified in the literature are presented.

CONCLUSIONS

Proteins previously unreported in the human vitreous were identified. The human vitreous proteome undergoes significant changes during embryogenesis and young adulthood. A number of protein levels change considerably during the second trimester, with the majority decreasing.

Pharmacologic vitreolysis with ocriplasmin: rationale for use and therapeutic potential in vitreo-retinal disorders

With increased knowledge about the origins and pathophysiology of vitreo-retinal disorders—and, in particular, the central role of anomalous posterior vitreous detachment in vitreo-maculopathies—a paradigm shift from surgery to pharmacotherapy is taking place with the development of pharmacologic vitreolysis. The first approved agent for pharmacologic vitreolysis therapy is ocriplasmin, a truncated form of the nonspecific serine protease plasmin. Twelve studies comprise the current ocriplasmin clinical trial program, demonstrating the efficacy and safety of a single intravitreal injection of ocriplasmin for the treatment of patients with symptomatic vitreo-macular adhesion or vitreo-macular traction, including patients with macular holes. Although post-approval implementation of ocriplamsin in clinical practice has shown success rates of up to 78%, there have been recent case reports of acute, transient visual dysfunction. There are thus new initiatives to further refine clinical indications for case selection and to identify possible untoward effects. Although more studies are warranted, it appears that ocriplasmin offers a good alternative to surgery. The future lies in pharmacologic vitreolysis, and the future of pharmacologic vitreolysis lies in prevention. Thus, long-term studies are needed to define a role for pharmacologic vitreolysis, in particular with ocriplasmin, in the prevention of progressive diabetic retinopathy and age-related macular degeneration.

Ultrasound-based quantification of vitreous floaters correlates with contrast sensitivity and quality of life

PURPOSE

Clinical evaluation of floaters lacks quantitative assessment of vitreous structure. This study used quantitative ultrasound (QUS) to measure vitreous opacities. Since floaters reduce contrast sensitivity (CS) and quality of life (Visual Function Questionnaire [VFQ]), it is hypothesized that QUS will correlate with CS and VFQ in patients with floaters.

METHODS

Twenty-two eyes (22 subjects; age = 57 ± 19 years) with floaters were evaluated with Freiburg acuity contrast testing (FrACT; %Weber) and VFQ. Ultrasonography used a customized probe (15-MHz center frequency, 20-mm focal length, 7-mm aperture) with longitudinal and transverse scans taken in primary gaze and a horizontal longitudinal scan through premacular vitreous in temporal gaze. Each scan set had 100 frames of log-compressed envelope data. Within each frame, two regions of interest (ROIs) were analyzed (whole-central and posterior vitreous) to yield three parameters (energy, E; mean amplitude, M; and percentage of vitreous filled by echodensities, P50) averaged over the entire 100-frame dataset. Statistical analyses evaluated E, M, and P50 correlations with CS and VFQ.

RESULTS

Contrast sensitivity ranged from 1.19%W (normal) to 5.59%W. All QUS parameters in two scan positions within the whole-central ROI correlated with CS (R > 0.67, P < 0.001). P50 in the nasal longitudinal position had R = 0.867 (P < 0.001). Correlations with VFQ ranged from R = 0.52 (P < 0.013) to R = 0.65 (P < 0.001).

CONCLUSIONS

Quantitative ultrasound provides quantitative measures of vitreous echodensity that correlate with CS and VFQ, providing objective assessment of vitreous structure underlying the functional disturbances induced by floaters, useful to quantify vitreous disease severity and the response to therapy.

Long-term results of office-based pneumatic retinopexy using pure air

AIMS

The long-term results of office-based pneumatic retinopexy (PR) using only filtered air were evaluated in a case series of rhegmatogenous retinal detachments with more than 3 years of follow-up, on average.

METHODS

77 cases of primary rhegmatogenous retinal detachments arising from superior tears (mean=1.6 tears) were treated with cryopexy (n=61) or laser (next day, n=16) and intravitreal injection of pure air in an office setting. The macula was detached preoperatively in 37 eyes (48.1%). Outcome measures were single-operation success, final reattachment rates and visual acuity (VA).

RESULTS

Subjects were followed for 6-186 months (mean follow-up = 40.7 months, 46.8% ≥ 2 years, 25% ≥ 5 years). In all cases, the air bubble was gone within 5 days. Single-operation success was achieved in 62/77 (80.5%) eyes. Repeat PR was successful in four cases, increasing the PR reattachment rate to 85.7%. Scleral buckle was performed on the remaining 11 eyes (14.3%), 1 with vitrectomy. The final reattachment rate was 100%. VA improved ≥ 2 Snellen lines in 53.2% of patients, with 50/77 (64.9%) attaining VA ≥ 20/40. Following PR, 87% of subjects had the same or better VA.

CONCLUSIONS

Office-based pure-air PR achieves acceptable reattachment rates with good visual outcomes and long-term efficacy. Eliminating the need for expansile gases makes this approach more widely available, decreases recovery time and lowers healthcare costs.

Vitreoschisis in macular diseases

OBJECTIVES

Vitreoschisis is a possible pathogenic mechanism in macular diseases. Thus, the vitreoretinal interface was evaluated in monkey eyes and patients with various macular diseases in search of vitreoschisis. It is hypothesised that vitreoschisis is present in macular holes (MH) and macular pucker (MP), but not in other maculopathies.

METHODS

Histopathology was studied in 14 monkey eyes and a vitrectomy specimen of a patient with macular pucker. Optical coherence tomography/scanning laser ophthalmoscopy (OCT/SLO) was performed in 239 eyes: 45 MH, 45 MP, 51 dry age-related macular degeneration (AMD), 53 non-proliferative diabetic retinopathy (NPDR) and 45 controls.

RESULTS

Immunohistochemistry demonstrated lamellae in the posterior vitreous cortex of 12/14 (86%) monkey eyes. With OCT/SLO, vitreoschisis was detected in 24/45 (53%) MH and 19/45 (42%) MP eyes, but in only 7/53 (13%) NPDR, 3/51 (6%) AMD and 3/45 (7%) control eyes (p<0.001 for all comparisons). Rejoining of the inner and outer walls of the split posterior vitreous cortex was visible in 16/45 (36%) MH eyes and 15/45 (33%) MP eyes. Histopathology of the MP specimen confirmed a split with rejoining in the posterior vitreous cortex.

CONCLUSIONS

Vitreoschisis was detected in half of eyes with MH and MP, but much less frequently in controls, AMD and NPDR patients. These findings suggest that anomalous PVD with vitreoschisis may be pathogenic in MH and MP.

Regression of choroidal neovascularization after vitrectomy for postinjection endophthalmitis

PURPOSE

To report regression of choroidal neovascularization following vitrectomy for endophthalmitis after antivascular endothelial growth factor injections.

METHODS

Observational case series of two patients with exudative age-related macular degeneration.

RESULTS

Endophthalmitis developed 2 days after the fourth ranibizumab injection in 1 case and 1 day after the ninth bevacizumab injection in another case. Vitrectomy and intravitreal antibiotic injections were performed. There was no bacterial growth on the cultures. Postoperative fluorescein angiography and combined optical coherence tomography/scanning laser ophthalmoscopy showed regression of choroidal neovascularization that was sustained after 29 and 32 months follow-up.

CONCLUSION

In both patients with active exudative age-related macular degeneration, regression of choroidal new vessels occurred after vitrectomy and injection of intravitreal antibiotics for the treatment of endophthalmitis. Removal of the posterior vitreous during vitrectomy may have eliminated the contribution of vitreous to exudative age-related macular degeneration and choroidal neovascularization.

Vitreopapillary adhesion in macular diseases

PURPOSE

The effect of vitreopapillary adhesion (VPA) in macular diseases is not understood. Spectral-domain optical coherence tomography/scanning laser ophthalmoscopy (SD-OCT/SLO) was used to identify VPA in macular holes, lamellar holes, macular pucker, and dry age-related macular degeneration (AMD).

METHODS

Ultrasonography and SD-OCT/SLO were performed in 99 subjects: 17 with macular holes, 11 with lamellar holes, 28 with macular pucker, 15 with dry AMD, and 28 age-matched controls. Outcome measures were the presence of total posterior vitreous detachment (PVD) by ultrasound and the presence or absence of VPA and intraretinal cystoid spaces by SD-OCT/SLO.

RESULTS

PVD was detected by ultrasound in 26 (92.9%) of 28 eyes with macular pucker, 6 (54.5%) of 11 eyes with lamellar holes (P = .01), and 4 (23.5%) of 17 eyes with macular holes (P = .000003). SD-OCT/SLO detected VPA in 15 (88.2%) of 17 eyes with macular holes, 11 (39.3%) of 28 age-matched controls (P = .002), 4 (36.4%) of 11 eyes with lamellar holes (P = .01), 4 (26.7%) of 15 eyes with dry AMD (P = .0008), and 5 (17.9%) of 28 eyes with macular pucker (P = .000005). Intraretinal cystoid spaces were present in 15 (100%) of 15 eyes with macular holes with VPA. In eyes with macular pucker, 4 (80%) of 5 with VPA had intraretinal cystoid spaces, but only 1 (4.3%) of 23 without VPA had intraretinal cystoid spaces (P = .001).

CONCLUSIONS

VPA was significantly more common in eyes with macular holes than in controls or eyes with dry AMD, lamellar holes, or macular pucker. Intraretinal cystoid spaces were found in all eyes with macular holes with VPA. When present in macular pucker, VPA was frequently associated with intraretinal cystoid spaces. Although these investigations do not study causation directly, VPA may have an important influence on the vectors of force at the vitreoretinal interface inducing cystoid spaces and holes.